Thiols in Beer

lovers are well aware of the wide range of flavors and aromas that can be found in their favorite brews. From hoppy and citrusy to malty and caramel-like, the variety seems endless. However, one group of compounds that is often overlooked but plays a significant role in the sensory experience of beer is thiols.

Thiols, also known as mercaptans, are organic compounds that contain a sulfur atom bonded to a hydrogen atom. These compounds are responsible for the distinctive aromas and flavors found in certain beers, particularly those brewed with specific hop varieties. high in thiols include Nelson Sauvin, Amarillo, Mandarina Bavaria, Mosaic, Citra, Cascade, Calypso, and Tomahawk.

One of the most notable thiols found in beer is 3MHA. This compound is known for its complex citrus and boxtree rhubarb flavor. Beers can contain up to 5,000 parts per trillion of 3MHA, contributing to their unique taste profiles. In lower concentrations, thiols can give beer a grapefruit pith and passion fruit-like flavor. However, in higher doses, they can impart smoky, skunky, tar, and even chocolate-like notes.

The presence of thiols in beer is not a coincidence. These compounds are formed during the process when certain hop varieties are added to the beer. The thiols are released from the hops and become trapped in the beer, contributing to its overall flavor and aroma. The exact mechanisms of thiol formation in beer are still not fully understood, but it is believed to involve the breakdown of precursor compounds during fermentation.

Thiols are not only responsible for the unique flavors and aromas in beer, but they also have practical applications in the brewing industry. Their soft electron donor properties make them excellent chelators of heavy metal ions. This means that thiol-containing drugs can be used to remove heavy metals from the body, preventing them from blocking enzyme activity and promoting oxidation.

Thiols are fascinating compounds that play a crucial role in the sensory experience of beer. From their contribution to complex flavors and aromas to their potential medicinal applications, thiols are an important aspect of the brewing process. So, the next time you enjoy a hop-forward beer with hints of grapefruit or passion fruit, remember that thiols are likely responsible for those delightful flavors. Cheers to the wonders of thiols in beer!

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Which Hops Are High In Thiols?

Hops that are high in thiols include:
– Nelson Sauvin
– Amarillo
– Mandarina Bavaria
– Mosaic
– Citra
– Cascade
– Calypso
– Tomahawk

These hops contain significant amounts of thiols, specifically 3-methyl-2-butene-1-thiol (3MBT) and 3-mercaptohexan-1-ol (3MH), which contribute to their unique flavors. Additionally, another thiol compound called 3-mercaptohexyl acetate (3MHA) is present in these hops, adding to the complex citrus and boxtree rhubarb flavors commonly associated with them.

It is worth noting that these bound thiols can be found in beers in concentrations of up to 5,000 parts per trillion, highlighting their impact on the overall flavor profile of hop-forward beers.

What Does Thiol Taste Like?

Thiols, when tasted in lower doses, can have flavors reminiscent of grapefruit pith and passion fruit. However, when consumed in higher amounts, the taste of thiols can change and become more intense, giving off smoky, skunk-like, tar, and even chocolate flavors. The taste of thiols can vary depending on the specific compound and concentration present. Here is a breakdown of the different flavors associated with thiols:

1. Lower doses:
– Grapefruit pith: Thiols can exhibit a tangy and slightly taste similar to the pith of a grapefruit.
– Passion fruit: Thiols can also have a tropical and sweet flavor resembling that of passion fruit.

2. Higher doses:
– Smoky: Thiols in higher concentrations can give off a smoky taste, similar to the aroma of burning wood or charcoal.
– Skunk: Some thiols are known for their pungent aroma, often described as skunk-like. This strong and unpleasant smell can also translate into a taste.
– Tar: Thiols can have a distinct tar-like taste, which is often characterized as bitter and heavy.
– Chocolate: In certain cases, thiols can contribute to a chocolate-like taste, adding richness and depth to the overall flavor profile.

It is important to note that the perception of taste can vary among individuals, and some people may have different interpretations of the flavors associated with thiols. Additionally, the specific thiol compound and its concentration play a significant role in determining the taste experienc


Thiols play a crucial role in the flavor and aroma profile of beer. Hops containing high levels of thiols, such as Nelson Sauvin, Amarillo, Mandarina Bavaria, Mosaic, Citra, Cascade, Calypso, and Tomahawk, contribute to the complex citrus, grapefruit pith, passion fruit, and even rhubarb flavors found in certain beers.

However, it is important to note that thiols can also have negative characteristics when present in higher doses. They can give off smoky, skunk-like, tar, and even chocolate-like aromas and flavors, which may not be desirable in certain beer styles.

Thiols can be formed through various chemical reactions involving alkyl halides, sodium hydrosulfide, olefins, and hydrogen sulfide. These compounds are known for their ability to readily form complexes with metal ions, such as copper, lead, and mercury. This property makes thiol-containing drugs effective in chelating heavy metal ions, preventing them from blocking enzyme activity and promoting oxidation in the body.

In the context of beer, thiols contribute to the overall sensory experience and are a key factor in the appreciation of different beer styles. Brewers carefully select and utilize hop varieties known for their thiol content to achieve specific flavor and aroma profiles in their beers.

Understanding the role of thiols in beer allows brewers to create unique and enjoyable drinking experiences for beer enthusiasts. By harnessing the potential of thiols, brewers can continue to push the boundaries of beer flavor and deliver innovative and exciting products to consumers

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Thomas Ashford

Thomas Ashford is a highly educated brewer with years of experience in the industry. He has a Bachelor Degree in Chemistry and a Master Degree in Brewing Science. He is also BJCP Certified Beer Judge. Tom has worked hard to become one of the most experienced brewers in the industry. He has experience monitoring brewhouse and cellaring operations, coordinating brewhouse projects, and optimizing brewery operations for maximum efficiency. He is also familiar mixology and an experienced sommelier. Tom is an expert organizer of beer festivals, wine tastings, and brewery tours.